The subject matter described herein relates generally to methods and systems for controlling an operational parameter of a wind turbine, and more particularly, to methods and systems for controlling operational parameters of a wind turbine tailored to another operational parameter.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extend from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
In known wind turbines, the yaw angle of the wind turbine (i.e., the horizontal misalignment between wind and turbine pointing direction) can be adapted so that the energy yield is improved, e.g., when the wind changes its direction. By adapting the yaw angle to the actual wind angle, the power output is maximized.
However, the yaw angle of the wind turbine influences not only the energy yield, but also the amount of load on non-yawing support structure parts of a wind turbine (such as tower, bearings, and the like). The support structure parts of a wind turbine are designed corresponding to a peak value. For instance, the operational parameters of the wind turbine may be set so that the load on the structural parts does not exceed a predetermined peak value. That means for example that the wind turbine has to be shut off or curtailed in some cases in order to stay within the design load levels of the structural, non-yawing parts of the wind turbine.
Traditional design load calculations take the fatigue loading for the support structure by default as being axi-symmetric with respect to the yawing axis of the wind turbine. This may lead to the situation where the turbine support structure is over-dimensioned due to a directional variation in short-term and long-term wind conditions. It is therefore desirable to permit a better use of the turbine fatigue reserve margins and a higher energy production by capturing more power for various wind directions.